The production of hydrogen peroxide from oxygen and hydrogen in the liquid phase with complexed metals such as those of the platinum series (ruthenium, rhodium, palladium, iridium and platinum) has been proposed. In general, the metal in a low valence is oxidized by oxygen to a higher valence and reduced by hydrogen back to the low valence state. The net reaction is the formation of hydrogen peroxide from hydrogen and oxygen.
The reduction of oxygen to hydrogen peroxide by hexaamineruthenium(II) and by tris(ethylenediamine) ruthenium(II) has been reported by J. R. Pladziewicz et al in Inorg. Chem, vol. 12, pp. 639-43 (1973). In both cases, the hexacoordinated ruthenium(II) complex was produced by the reduction of the corresponding hexacoordinated ruthenium(III) complex with metals such as europium(II) or a zinc-mercury amalgam.
Hydrogen sulfide is a by-product of many industrial processes including petroleum cracking and purification and generally represents a disposal problem rather than a useful chemical feedstock. The use of hydrogen sulfide as a reducing agent, especially in catalytic systems, is sharply limited by the tendency of sulfur to participate in side reactions including the irreversible formation of metal sulfides with metal catalyst, thus poisoning the catalyst.